In order to use .htaccess files to set the include path, PHP must be installed as an Apache module. If PHP is compiled as a CGI binary, you can set the include path in a custom php.ini file (if, for example, you're being hosted somewhere and don't have access to the main php.ini file. Note that custom php.ini files don't affect subdirectories in the way that .htaccess files do, so you'll need to put your custom php.ini file in any subdirectories as well.